Styrofoam is not just for landfills anymore
Scientists have pioneered a technique that could transform used Styrofoam, also known as polystyrene, into a biodegradable plastic.
Tue, Aug 01, 2006 at 03:09 PM
Styrofoam has had a bad rap for a long time, and with good reason: Each year, Americans throw away 2.3 million tons of packing peanuts, used coffee cups and other Styrofoam products. And once landfilled, they can take millions of years to disintegrate. But recently, scientists at University College Dublin have pioneered a new technique that could transform used Styrofoam, also known as polystyrene, into a biodegradable plastic.
The process is made possible by a bacterium called Pseudomonas putida, which occurs naturally in soil. In their experiments, scientists heated polystyrene to 968 degrees Fahrenheit in an oxygen-free environment (because there is no oxygen, there is no burning and therefore no emissions). This process, called pyrolysis, breaks down the chemical bonds in Styrofoam to make styrene, which is readily digestible by the bacteria. Fed styrene under proper conditions, the bacteria produce polyhydroxyalkanoate (PHA), a biodegradable plastic that can be used to make disposable utensils, shampoo bottles, even medical devices like heart stents. And PHA-based products can be tossed onto your compost pile when you’re done with them. This new bacterialdigestion process might also have wider applications than recycling your office coffee cups — scientists say it could probably be used to process plastic waste from the petrochemical industry as well.
As of yet, PHA has not been commercially viable because it’s more expensive to produce than petroleum-based plastics, and the process for making it is far less energyefficient. But if scientists can use this new technique to manufacture PHA on a wider scale, the material may become more costeffective. Worldwide, the process could also save more than 15 million tons of polystyrene (about the weight of 5 million Hummer H2s) from being thrown away. Perhaps Styrofoam, the material we all love to hate, will finally acquire some eco-street cred.
Story by Jacqulyn Lane. This article originally appeared in Plenty in August 2006. This story was added to MNN.com in June 2009.